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Physics from HERA-B

Physics from HERA-B. Outline. Data samples Physics topics Pentaquark searches y (2S) production A –dependence bb cross section Summary. 58 th PRC Open session, October 28 th , 2004 M. Mevius, DESY Hamburg. -. Data samples. Minimum Bias data. 200 M events on C,Ti,W

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Physics from HERA-B

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  1. Physics from HERA-B Outline • Data samples • Physics topics • Pentaquark searches • y(2S) production • A –dependence • bb cross section • Summary 58th PRC Open session, October 28th, 2004 M. Mevius, DESY Hamburg - 58th PRC M.Mevius

  2. Data samples Minimum Bias data 200 M events on C,Ti,W 1000 ev/s > 1TB/day Dilepton triggered data 150 M dilepton trigger events 300 000 J/ (>1000 per hour) 15 000 c 5 000 (2S) 35 M Hard photon trigger 58th PRC M.Mevius

  3. Topics under study • Upper limit on BR(D0m+m-) (Phys.Lett.B596:173-183,2004) • Pentaquark searches (pKs, Xp) (hep-ex/0408048) accepted by Phys. Rev. Lett. • Inclusive bb cross section • Upsilon cross section • Production of f and K* mesons • y(2S) production • D+/D0 production ratio • J/y cross section in MB _ 58th PRC M.Mevius

  4. Topics cont’d • Hard photon production • L0 polarization • cc production • A dependence charmonium production • J/y differential distributions • V0 and hyperon production • Jet production 58th PRC M.Mevius

  5. +,-- Searches  mass pK0s mass NA49 HERA-B UL(95%) -- UL(95%) mass GeV/c2 1.4 1.475 1.55 1.625 1.7 (hep-ex/0408048) accepted by Phys. Rev. Lett. Counts Counts B d/dy b/C B d/dy b/C UL(95%)Bd/dy|y=0 = 4-16 b/N @ 1521-1555 MeV/c2 + / (1520) < 3 – 12 % UL(95%)Bd/dy|y=0 = 2.5 b/N @ 1862 MeV/c2 -- / -< 3/B% -- / (1530)0< 4/B% 58th PRC M.Mevius

  6. y(2S) / J/y Production Ratio Br’·s(y’) [%] Br·s(J/y) √s preliminary Preliminary results for A preliminary 58th PRC M.Mevius

  7. y(2S) differential distributions dσ/dpT2 xF < 0 e+e- dσ/dxF preliminary preliminary preliminary m+m- preliminary 58th PRC M.Mevius

  8. J/y A dependence • only 1 target config (C-W) • ~15 % of m+m– sample similar results for e+e- • Hera-B normalization • Statistical errors only preliminary I1I2 I1I2 preliminary PT 58th PRC M.Mevius

  9. _ bb production _ b(b)  B  J/ + X J/  m+m- ; e+e- Measurement relative to direct J/ production to minimize trigger/reconstruction uncertainties R= relative efficiency1 • B Selection: • Lepton impact to the wire • Distance of J/ to wire B selection eff. from MC 30-45% 58th PRC M.Mevius

  10. _ bb production preliminary preliminary Full statistics 20% sys. error under investigation main contribution: Br(bbJ/X) = 2.320.20% - E771/E789 : scaled to 41.6 GeV (J/)=357 ± 2 ± 36 nb/nucleon 58th PRC M.Mevius

  11. Summary • Good data quality • Several QCD related results expected • Preliminary results on most topics presented at conferences (>40) • 2 papers finished (BR(D0m+m-) (UL),pentaquark (UL)) • Publication on advanced analyses in preparation (bb, U, D+/D0, f/K*, J/y, y(2S),...) • Other topics could lead to publication, manpower permitting • Analysis will continue until end 2005 - 58th PRC M.Mevius

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